Saddam's WMD in Syria?

Is it possible that any of the chemical weapons the Syrian regime is now threatening to use originated in Saddam Hussein's Iraq? I recall looking at satellite images of trucks moving something from Iraq to Syria--coupled with furtive visits from Russian diplomats--in the weeks leading up to the war in Iraq. This Wikipedia page details the Syria theory, among many others, regarding Saddam's WMD, which, if I need remind anyone, we know he once had as he used chemical weapons against the Kurds. (This isn't an argument for or against the war in Iraq; just speculation about a mystery I've long found intriguing.)